Epidemiological Profile of Newly Diagnosed Patients with Hepatitis C Infection in 6 Health Regions Across Canada Over and 8-Year Period

Objectives To evaluate epidemiological profile and patterns of hepatitis C virus (HCV) infection over an 8-year period in Canada through the Enhanced Hepatitis Strain Surveillance System. Methods Demographic, clinical, and potential risk factor information on newly diagnosed HCV infection in 6 health regions across Canada, from 1998 to 2006, was collected using standardized questionnaires. Results During this time period, the reported cases of HCV infections per 100,000 population declined by 61% from 91.3 in 1998 to 35.3 in 2006 (p<0.001). Risk factors were indicated in 9504 (99%) of participants; 684 (7%) had one (most frequently injection drug or blood exposure), 1083 (11%) had two, and 7737 (81%) had more than two risk factors. Compared to younger HCV patients, older patients were more likely to have exposure to blood products (32% vs. 17%; p<0.001) but less likely to have injection drug use (59% vs. 74%; p<0.001). Proportion of newly diagnosed patients associated with blood transfusion before 1990 significantly declined (p<0.05) from 16.7% in the period 1998 to 2000, to 13.5% in the period 2004 to 2006. Conclusion The above figures are useful for evaluating the epidemiological changes of HCV infection and for anticipating the future economical cost of the hepatitis C treatment. The recognition of the potential presence of multiple risk factors may have important implications determining approaches to HCV surveillance, particularly the use of hierarchical algorithms in the study of risk factors.